The present invention relates to a drive assembly for a manually driven vehicle, in particular a bicycle or a pedelec, comprising an electric auxiliary drive, the drive assembly comprising a first drive shaft for a manual drive and a rotor of the electric auxiliary drive, the first drive shaft and the rotor of the electric auxiliary drive being coupled to a common output element.
The present invention also relates to a vehicle comprising a drive assembly of this kind. The present invention further relates to a method for controlling a drive assembly for a manually driven vehicle comprising an electric auxiliary drive. The present invention also relates to a method for controlling a vehicle, in particular a bicycle or a pedelec. The present invention further relates to the use of a strain wave gear for additively combining a manual drive and an electric auxiliary drive.
Manually driven vehicles, in particular bicycles or pedelecs, in which a pedaler driving the vehicle by muscular power is assisted by an electric auxiliary motor have been known for a long time. For example, WO 91/19637 A1 discloses planetary gearing for hybrid vehicles, in which a sun gear meshes with a plurality of planet gears on a central hub comprising a centered flange, one side of which planet gears is connected to the planet carrier by means of screws and the other side of which is connected to the flange and thus to the hub. Furthermore, the Swiss patent application CH 705521 A2, for example, discloses a drive system comprising planetary gearing for vehicles driven by muscular power and by an electric auxiliary motor, in which a planetary gear set and the electric auxiliary motor are accommodated in a housing which forms the hub of the driving wheel. In this case, the sun gear driven by the auxiliary motor and the outer ring driven by the muscular power are rotatably mounted on a central, non-rotatable spindle that is connected to the frame of the vehicle, and the planet carrier is torque-transmittingly coupled to the driving wheel of the vehicle that forms the hub housing.
Furthermore, EP 0 569 954 A1 discloses a bicycle comprising an electric motor having a torque sensor provided for determining the pedal force, and a corresponding controller for the electric drive. Furthermore, the Japanese document JP-H-0899686 A, for example, discloses a motor-assisted drive system for a bicycle comprising a torque sensor on the chain drive in the rear wheel. Furthermore, JP 2011-168180 A also discloses a drive-assisted bicycle of this kind comprising a torque sensor for determining a pedal torque.
Moreover, AT 40138, for example, proposes a motor gear assembly for an electric drive of vehicles, in particular bicycles, and proposes an ironless disk armature and a cycloidal gear.
In this case, a flange which separates the motor from the gear in the axial direction is designed having a permanent field return path, the disk armature being connected to a hollow shaft and being mounted on the flange by means of said shaft, and, on the drive side, the gear being mounted on the hollow shaft and on a part that engages over the gear.
However, the proposed drive assemblies for assisting manual drives by means of a motor generally require a relatively large amount of installation space. Furthermore, the mechanical design thereof is relatively complex. Finally, torque sensors should often be provided so as to allow an electric auxiliary drive to be controlled in order to couple the power from the electric auxiliary drive into the manual drivetrain.
An object of the present invention is therefore to provide a drive assembly for a manually driven vehicle, in particular a bicycle or a pedelec, which has a simple and compact design and makes it possible to couple an electric drive into the manual drivetrain without using any torque sensors.